base-files: Explicit include iopsys.sh and common.sh

When non active boot image do not contain iowrt_image_version|name within FIT attribiutes the old way of extracting version is used.

On newest software there are errors during execution of get_iopsys_version function from iopsys-fwbank.sh about not found sh functions.

Explicit include iopsys.sh and common.sh to inform fwbank script about missed functions definitions.